I use a combination of Excel and notepad++ (or some other text editor) to manipulate small datasets but in this case you don't need to worry about that because that dataset is part of the sample runs that ship with GeneXproTools (the Breast Cancer classification sample).

Records containing ? are missing records and GeneXproTools automatically replaces them with zero (in this case) so you don't have to do anything. Later, and if you want, you can change them to a different value you deem more appropriate by choosing the menu Data->Missing Values Mapping, selecting the variable with the missing values and changing the mapping as in the attached image.